1. Technical Field of the Invention
The present invention relates in general to the telephony field and, in particular, to a method and system for attaining interoperability between an Intelligent Network (IN) and Packet Data Network (PDN).
2. Description of Related Art
Packet-switched communications standards have been specified for digital cellular telecommunications systems in both Europe and Japan. For example, standards for the General Packet Radio Service (GPRS) have been specified for the Pan-European Global System for Mobile Communications (GSM) by the European Telecommunications Standards Institute (ETSI), the Packet Personal Digital Cellular (PPDC) System by the Nippon Telephone and Telegraph Company (NTTC) in Japan, and packet-switched standards are being specified for the International Mobile Telecommunications-2000 (IMT-2000) System. These packet-switched communications systems being developed are considered more efficient than conventional circuit-switched communications systems in transferring information such as audio, video and data in a mobile radiotelephone system environment. Albeit, the efficiency is likely higher for circuit-switched voice, but the efficiency is higher for packets than the same coding used for circuit-switched data. However, it is assumed that in the initial operational years, the packet-switched communications systems will be used primarily for accessing and transferring Intranet (e.g., companies"" local networks) and Internet (e.g., World-Wide Web or WWW) data, while the conventional circuit-switched systems will still provide the traditional bearer services (e.g., voice calls).
For some time now, mobile communications network operators (e.g., GSM, PDC and IMT-2000 network operators) have been providing certain value-added services such as, for example, the new IN/Customized Applications for Mobile network Enhanced Logic (CAMEL) service. CAMEL is a feature in the GSM Standard that integrates support of operator-specific IN services into the GSM architecture. Essentially, the CAMEL services are overlaid on top of the GSM circuit-switched traffic (e.g., voice calls). However, a problem that exists is that there is currently no known capability for overlaying these value-added services on packet-switched traffic. The main reason for this problem is that this capability is expected to be provided by the Intranet operator or Internet Service Provider (ISP), and not as part of the value-added service (e.g., IN/CAMEL) itself.
Currently, no international standard is being promulgated for an interface between an IN and packet-switched network, and as mentioned earlier, there is no known solution for the problem of how to provide value-added services (e.g., CAMEL) for packet-switched communications. As such, this is an immediate problem for mobile communications network operators who are currently providing IN services, such as, for example, the popular pre-paid services being offered for mobile subscribers"" circuit-switched calls (e.g., voice calls and G3 facsimile calls). Such pre-paid IN services monitor the elapsed time of the circuit-switched call for a mobile subscriber, and translate that time into charges that are billed to the subscriber in proportion to the communications time used. However, there is currently no method or system available that enables a pre-paid IN service application to monitor the elapsed communications time for a subscriber using packet-switched communications.
Consequently, a pressing need has arisen for a PDN/IN interface and interoperability which will enable such services as IN/CAMEL to be overlaid on top of packet-switched traffic as a complement to conventional Intranet and Internet value-added services. As described in detail below, the present invention successfully meets this need and resolves these and other related problems.
In accordance with a preferred embodiment of the present invention, a method and system are provided for creating an interface between a packet-switched network and an IN, which is based on an interface between an associated circuit-switched network and an IN/CAMEL service. Meanwhile, the CAMEL application can also provide IN services to mobile subscribers while they are roaming in other networks (e.g., international roaming).
An important technical advantage of the present invention is that mobile network operators providing IN/CAMEL services to offer a pre-paid subscription to mobile users, which will cover traditional voice calls and also Intranet and Internet usage through a packet-switched communications standard.
Another important technical advantage of the present invention is that a mobile user of circuit-switched and packet-switched communications can subscribe with one network operator to provide a pre-paid service and pay in advance only once for the subscription. The network will subtract payments from the user""s account for both the circuit-switched and packet-switched traffic.
Still another important technical advantage of the present invention is that a viable interface and interoperability are provided between a packet data node and an IN/CAMEL node, which can be used to overlay CAMEL services on packet communications as a service complement to Intranet and Internet value-added services.